1. Field of the Invention
This invention relates to water pumps and, more particularly, to heat-powered water pumps.
2. The Prior Art
Throughout the world there are many places where fuel and electrical power are expensive because of limited fossil fuel deposits, transportation difficulties and locations remote from electrical generating stations. Furthermore, the local production of electrical energy by combustion engines is expensive when considering the costs associated with the initial equipment purchase, fuel, transportation of the fuel, repairs and the need for a relatively high degree of technical sophistication for the repairs. In addition, projected fossil fuel shortages will result in continually increasing fuel costs.
However, a relatively cheap and abundant energy source is necessary for a high material standard of living. It is only when humanity can multiply mechanical work many times beyond muscle power that enough goods and services can be produced to provide the economic conditions for a reasonably satisfactory standard of living. Although fuel and energy are reasonably available and at a relatively reasonable cost in the currently industrialized areas of the world, in the remote areas of the world the relatively high cost for fuel and energy, particularly electrical energy, substantially inhibits the further development of those portions of the world. For example, vast areas of the world are suitable for irrigation with relatively abundant sources of water being relatively readily available. However, these areas also require an economical technique for raising the water from the relatively shallow water table or nearby stream to the surface for irrigation. Most primitive devices for lifting this water includes simple devices operated by one or two men or through the use of animal energy. However, the use of manpower to pump water is particularly wasteful of man's labor since man's labor can be more economically utilized in providing goods and services rather than mechanical energy. Furthermore, animals also consume food grown on irrigated land, part of which might otherwise be used for human consumption.
Coincidentially, although there are many parts of the world where fuel and electrical power are expensive because of long distances from the natural deposit, transportation difficulties etc., these locations are also generally endowed with an abundance of available solar energy. Currently, the only inexhaustable source of energy available is solar energy. Solar energy or solar flux is customarily measured in langleys per minute, one langley being equivalent to one calorie of radiation energy per square centimeter. The intensity of the solar flux varies with geographical location, time of day, season, cloud cover, atmospheric dust, and the like. This intensity varies between about 0 and 1.5 calories per square centimeter per minute. Therefore, assuming a solar flux of one langley per minute, a one square meter surface receives 10,000 calories per minute. With an overall average of one langley per minute for 500 minutes per day (which is slightly more than 8 hours), a 100 square meter surface receives, in bright sunshine, about 500,000 kilocalories per day. This energy is the equivalent in thermal energy to burning about 14 gallons of gasoline.
Accordingly, on a comparative basis, solar energy does appear to be feasible in providing the necessary energy for the efficient pumping of water. Although solar energy is produced only while the sun is shining, pumping irrigation water, which involves no storage of power, offers a good area for the early use of solar energy. For those times when the sun is not shining, substitute thermal energy could be obtained from burning agricultural wastes such as stubble, weeds, chaff and the like. In these situations, the economic comparisons between solar energy and other energy sources appear to be sufficiently advantageous to encourage further research and development of solar energy.
Additional information regarding solar applications can be found in APPLIED SOLAR ENERGY, Adden B. Meinel and Marjorie P. Meinel, Addison-Westley Publishing Company, Reading, Massachusetts (1976) Library of Congress Catalog Card No. 75-40904, and DIRECT USE OF THE SUN'S ENERGY, Farrington Daniels, Ballantine Books, New York (1977) Library of Congress Catalog Card No. 64-20913.
Various types of water or fluid pumps operable from heat sources are shown in U.S. Pat. Nos. 2,050,391; 2,553,817; 2,688,922; 2,744,470; 2,757,618; 2,954,741; 2,973,715; 3,659,960; 3,765,799; and 3,790,305. However, the devices represented in each of the foregoing patents tend to be rather complex, expensive to fabricate and maintain, or require excessive monitoring for efficient utilization of energy. Each of these factors restrict the use of these devices in the less developed sections of the world.
In view of the foregoing, it would, therefore, be an advancement in the art to provide a heat-powered water pump which is operable to pump water from a relatively shallow location to an elevated location, the pump operating relatively independently of continuous monitoring and maintenance. In addition, it would be an advancement in the art to provide a heat-powered water pump which can utilize either solar energy or thermal energy from burning agricultural wastes. Such an invention is disclosed and claimed herein.